1. Technical Field
Exemplary embodiments of this disclosure relate to an image forming apparatus such as a printer, a facsimile, or a copying machine.
2. Description of the Related Art
Image forming apparatuses are used as, for example, copiers, printers, facsimile machines, and multi-functional devices having at least one of the foregoing capabilities. As one type of image forming apparatus, electrophotographic image forming apparatuses are known. As a conventional image forming apparatus of this type, an image forming apparatus described in JP-2001-147629-A (JP-3893232-B) is known. The image forming apparatus brings a transfer roller into contact with a photoconductor to form a transfer nip. A toner image formed on a surface of the photoconductor is transferred onto a recording sheet nipped in a transfer nip. Some amount of residual toner which has not been transferred onto the recording sheet may adhere to the surface of the photoconductor that has passed through the transfer nip. The residual toner is removed from the photoconductor surface with a cleaning device.
The cleaning device is configured such that a cleaning blade disposed in contact with the surface of the photoconductor is stored in a cleaning case and the cleaning blade scrapes residual toner after transfer from the photoconductor surface to collect the toner in the cleaning case. The toner collected from the photoconductor surface with the cleaning device, to be discarded or recycled, is transported with a toner transport device into a collected toner container disposed in a body of the image forming apparatus independently of the cleaning device.
The toner transport device disposed in the image forming apparatus described in JP-2001-147629-A has a transport housing that forms a falling transport path that is disposed in such a posture that it extends in a vertical direction to cause toner to fall by its own weight so as to transfer the toner. A through hole that communicates with the inside and the outside of a side wall with each other is formed in the side wall of the transport housing, and one end of a toner transport pipe to transport toner collected from the photoconductor surface with the cleaning blade is inserted into the through hole. The other end of the toner transport pipe is connected to the cleaning case to communicate with a discharge port formed in the cleaning case.
With the rotation of a transport screw rotatably disposed in the toner transport pipe, the toner is ejected from an ejection port formed in the end face of the one end from the inside of the cleaning case through the toner transport pipe and sent to the falling transport path in the transport housing. The toner sent to the falling transport path is transported by gravity falling in the falling transport path and finally transported into the collected toner container.
In the image forming apparatus described in JP-2001-147629-A, only one toner transport pipe is used to transport the toner collected from the photoconductor surface from the cleaning case to the falling transport path of the transport housing. However, in order to improve toner transport capability, a plurality of toner transport pipes may be disposed.
In this case, a plurality of through holes are formed in the side wall of the transport housing, the ends of the plurality of toner transport pipes are inserted into the through holes, respectively, the plurality of toner transport pipes are connected to a single falling transport path to integrate the transport paths into one, and the toner is transported into the collected toner container. In this manner, the configuration of a toner transport device can be made simple more than that obtained when falling transport paths are independently disposed for a plurality of toner transport pipes, respectively.
However, when the ends of the plurality of toner transport pipes are disposed by being inserted into the plurality of through holes formed in the transport housing, depending on the positional relationship between the toner transport pipes, toner ejected from the ejection port of one toner transport pipe is accumulated on the outer circumferential surface of another toner transport pipe. In this manner, when the toner is accumulated on the outer circumferential surface of the toner transport pipe, the accumulated toner is agglomerated and gradually grown to gradually narrow down the falling transport path so as to form a toner bridge, and the toner bridge blocks toner transport.
The above-described problem relates to toner transportation from the cleaning device for cleaning the photoconductor. However, a similar problem may be posed in a configuration of cleaning the intermediate transfer belt.